A stereoscopic display device is a new concept for an image display device for improving a quality level of visual information by providing a three-dimensional image similar to an actual image, which, to an observer, looks and feels quite different to a related art two-dimensional image. In general, the reason for which people experience a three-dimensional visual effect is well known, in that when people view an object, there is a time difference between images striking the right and left eyes. That is, since people's eyes are spaced apart from each other by about 65 mm, images from slightly different directions reach them, so that a three-dimensional effect is realized due to binocular disparity caused when stereoscopic images are displayed. As a result of this, stereoscopic images may be realized through a method of displaying images having a time difference to both of an observer's eyes.
A related art stereoscopic display device is largely classified into a display device with a pair of polarized glasses and a display device without polarized glasses. A stereoscopic display device using a pair of polarized glasses projects left- and right-eye images having different respective polarization properties which allow only a left-eye image to be projected onto a left-eye lens and only a right-eye image to be projected onto a right-eye lens through polarizing plates attached to the pair of polarized glasses, thereby providing a stereoscopic visual effect. This technique of using a pair of glasses requires a user to wear inconvenient polarized glasses, but has less viewing angle limitations and demands relatively simple manufacturing processes.
In general, a related art stereoscopic display device using a pair of polarized glasses includes an image generating unit, which includes a left-eye image unit for generating a left-eye image and a right-eye image unit for generating a right-eye image, and a filter unit, which alters polarization states of left-eye image light and right-eye image light generated from the image displaying unit.
At this point, the image generating unit may include a display panel such as a Liquid Crystal Display (LCD) and a Plasma Display Panel (PDP). For example, the image displaying unit includes a Thin Film Transistor (TFT)-array substrate, which includes a transistor and a pixel electrode, a color filter substrate, which includes a transparent electrode and a color filter layer, and liquid crystal cells, which are arranged two-dimensionally in a parallel direction or a vertical direction.
Furthermore, the filter unit includes a polarizing film, or a polarizing plate having a phase difference plate attached, all of which are patterned in correspondence to the left-eye image display unit and the right-eye image display unit, respectively. The filter unit is typically attached to an external color filter substrate.
However, in the case of the related art stereoscopic display device, since there is a thick glass substrate between an optical filter and a color filter layer of an image display unit, right-eye image light and left-eye image light from the image display unit are projected into respective opposite eyes, thereby causing crosstalk. As a result of this, it becomes difficult to obtain a clear three-dimensional image.
In addition, it is important to accurately position the pixels of an image display unit and the pattern of an optical filter in a stereoscopic image display device. However, when the pixels of the image display unit do not correspond to the pattern of the optical filter, right-eye image light and left-eye image light are not properly separated so that three-dimensional images may not be accurately obtained. Furthermore, in relation to the related art stereoscopic display device, it is difficult to precisely match the pixels of an image display unit and the pattern of an optical filter.